Destructive hydrogenation of carbonaceous material



DESTRUCTIVE HYDROGENATION OF CARBONACEOUS MATERIAL Filed March 7. 1934 Fig. 1.

EPPEHEA 7"E/? HEA T EXCHANGER H /N/ T/AL REACT/0N CHAMBER CARBON/1650 us c0/v TA/N/NG L UMPS MA TEP/AL 0F CA mus r c HYDTQOGEN COOL lNG DEV/CE UNCONDENSEO D 4 645555 sap/1m TING E VESSEL 1. IQU/D PRODUC 1'5 Fly. 2 //v/ TIA LA 0,4 RBON MA TERIA L PUL VE/Q/ZED 6 TE J CA TALYST 1. COOLER M/xilva L M VESSEL GAS SEPARA TING PUMP VESSEL L um ppoouc rs HYDROGEN INVENTORS PAUL HEROLD HERMANN KAUFMANN.

ATTORNEYS.

lytic destructive hydrogenation at temperatures Patented Oct. '27, 1936 PATENT OFFICE DESTRUCTIVE HYDROGENATION OF CARBONACEOUS MATERIAL Paul Herold and Herman Kaufmann, Leuna,

Germany, assignors to Standard-I. G. Company, Linden, N. .L, a corporation of Delaware Application March 7, 1934, Serial No. 714,372 In Germany October 31, 1930 1 Claim.

The present application is a continuation-inpart of our application Ser. No. 570,760, filed 23rd October, 1931, which relates to the destructive hydrogenation of carbonaceous materials in the presence of catalysts comprising complex compounds of a high order of the metals molybdenum and tungsten and in which has been claimed the use of isopoly acids and '-metallic complex acids of molybdenum and tungsten and the salts of the said acids.

In the conversion of distillable carbonaceous materials, such as coals of all varieties, tars,

mineral oils, their distillation and conversion products and other hydrocarbon products into hydrocarbons of the nature of benzines by cataranging between 300 and 700 C. and under a pressure of at least 20 atmospheres, preferably more than 50 atmospheres, it is already known that those catalysts are especially suitable, which contain the heavy metals of the 6th group of the periodic system, either alone, in the form of oxides, salts, such as carbonates, or sulphides and the like, if desired in admixture with each other or with other substances, as for example zinc oxide or magnesium oxide.

Among these substances, molybdenum, tungsten and the compounds thereof haveproved to be especially active catalyst components.

It has now been found that the said reaction, which is effected with gases comprising hydrogen, that is hydrogen or gases containing the same or also gases giving off hydrogen, at a temperature between 300 and '700 C., preferably between 380 and 600 C., and under pressures of at least-20 atmospheres,-preferably more than 50 atmospheres, proceeds with particular advantage in the presence of those heteropolymeric acids of molybdenum'or tungsten. which are free from phosphorus and in which the acid combined with the molybdic acid or tungstic acid is a non-metallic acid (i; e. in which the atom corn-- bined with the acid radicles containing molybdenum or tungsten and substituting the oxygen of the simple acid, which atom is also called central atom, isa non-metal) or the salts of these heteropolymeric acids such as ammonium silico molybdate ,or the free acids of these salts obtained by heating" the said ammonium salts to between 400 and 450 C., or by digestion of the different free acidsto be combined in the heteropoly'meric compound with water, evaporating the paste to dryness and heating to from about to 200- C. The gases comprising hydrogen are preferably employed in large excess and in the form of a stream.

As is known, heteropolymeric acids (see for example Einfiihrung in die Chemie der Komplexverbindungen, 1924, by Weinland, page 450 or Lehrbuch der Anorganischen Chemie, 1932, by Remy, 2nd vol., page 130, and following) are those acids which contain at least two difierent acid radicles in chemical combination of which usually one is in great excess over the other or others, as for example the silico molybdic acids, the silico tungstic acids, the molybdo chromic acids andother acids. It is assumed that in these heteropolymeric acids the oxygen atoms of an acid containing combined oxygen are substituted by radicles of at least one different acid as explained in the said book by Weinland.

Complex compounds of a higher order of the aforesaid nature and methods for their production are for example described-in Abegg-Auer- 20 bach ljandbuch der Anorganischen Chemie, Leipzig 1921, vol. 4, Part 1, second half, pages 1041 and following.

In order to obtain the catalysts in a suitable form it is very advantageous to mix them with 25 other non-reducible substances. By non-reduc- ,ible substances we understand oxides and salts .of metals which are not substantially altered by the attack of hydrogen up to a temperature of 450 c.

As examples of suchnon-reducible substances may be mentioned alumina, chromic oxide, kaolin and the phosphates of zinc, magnesium or aluminum. The said admixtures, which are usually employed in a finely pulverulent state, serve more particularly as binding agents to increase the solidity of the catalyst component. Between about 10 and 5.0 per cent by Weight of the said admixtures are advantageously contained in the resulting catalyst mass. It has been found that,

in order to maintain the complex structure, it

is necessary either to avoid all additions of a basic nature or so to regulate the amounts of such additions that in the final mixture the acid components are stoichiometrically considerably predominant compared with the basic cbmponents. Among the said basic components are includednot only the oxides, carbonates and other salts of volatile acids of the alkaline and alkaline earth metals and magnesium, but also 0 those of zinc, manganese and the like, while those of aluminum and the rare earth metals and of chromium are without injurious effect.

It is preferable to use the catalysts according to the present invention in a state free from 5 readily reducible compounds and from metals forming such compounds, as for example from iron and its compounds. By readily reducible compounds we understand such as are. reduced 5 by hydrogen to the metals, or a lower oxidation stage at a temperature up to 450 C., more particularly up to 400 C.

In the process according to the present invention the hydrogen is employed in excess, that is to say the space filled by hydrogen is greater, preferably more than 1.5 times greater, than that filled by the vaporized carbonaceous materials. The particular amount of hydrogen to be added depends upon the nature of initial material to be treated and on the nature of the desired products. For example, if it is desired to obtain products containing substantial proportions of aromatichydrocarbons by treatment at the upper temperature range of the destructive hydrogenation, about from 300 to 500 liters of hydrogen are employed for each kilogram of initial oil; when operating in the liquid phase 1.5 cubic meters of hydrogen may be added to each kilogram of initial carbonaceous material, while when working in the gaseous or vaporous phase for the production of lower boiling hydrocarbons without substantial conversion into aromatic hydrocarbons each kilogram of initial oil may be treated with v for example 2 cubic meters. It is, however, to be understood that the operation in the vaporized phase as well as that in the liquid phase may be effected also with the employment of larger amounts of hydrogen.

In case the catalyst is employed finely dispersed in the oil or paste of the solid carbonaceous material to be converted it is added to this oil or paste in an amount between 0.03 and 10 per cent of the amount of this oil or paste. the conversion is to take place in the vaporized 40 phase and the catalyst employed inthe form of pieces arranged in the reaction vessel the oil is 'usually sprayed in an amount per hour of from half to three times the amount of the catalyst. Y The materials to be converted are preferably 4 exposedfor between 0.5 andi hour to the reaction conditions, but also higher or smailer periods of exposure may be employed.

The catalysts according to the present invention are considerably superior in activity to those whose-active component (as for example molybdenum) is present in non-complex form. as for" example in magnesium molybdate, M gMoOa or in simply complex form. Under the same conditions they give for greater yields of degradation products and the splitting reaction sets in at much lower temperatures so that the same or even a v better eiiect is obtained at lower temperatures than is-obtainable with the catalysts and under the temperature conditions hitherto employed;

this constitutes a considerable advance in economy.

The special suitability of the said catalysts for the production or benzines from middle oils resides in the fact that they are capable even at comparatively low temperatures of yielding products containing large amounts of hydrocarbons boiling below 100 0., so that the whole of the 'benzines obtained may be directly employed as f motor fuels. The catalysts are ofparticular advantage when working in the gaseous or vaporous, I phase, these phases hereafter being referred to as vaporized phase" although good results are The saidcatalystsare. w by their also obtained when working in= the liquid phase.

property of being immune to poisoning by sulphur.

The process is preferably carried out in a circulatory system. Care should preferably be taken that materials such as iron which would give rise to the formation of methane and the separation of .carbon should not be present in those parts of I 'the apparatus which come into contact with the hot reacting materials. Accordingly these parts should preferably be made of or coated with high- 1y alloyed steels or aluminium and the like. Care should also be taken to provide for an intimate contact. between the materials to be destructively with hydrogen under pressure with or without the aid of catalysts and thus converted into middle oils which are then treated in the manner hereinbefore described. suitableapparatus for carrying out ourp is illustrated in the accompanying drawing in which Figure 1 is a skeleton view of an apparatus for operating in the vapor phase and Figure 2 is a skeleton view of an apparatus for operating in the liquid phase.

Referring to Figure 1 in detail, the initial ma-- terial is fed in the liquid state into pipe I: which conducts it to point c where it Joins pipe a into which a stream of hydrogen is fed. The mixture of initial material and hydrogen passes through heat exchanger A, in which it is vaporized, then through preheater B into the reaction chamber C which contains pieces of catalyst. The products are conducted from chamber 0 back to exmixed with pulverized catalyst introduced irom hopper H. J designates a stirrer. 1"rornthe mixing vessel,, the v mixed initial material and catalystispumpedthroughapipetothepreheater K. Before reaching preheater K. it is mixed! with hydrogen at x. The mixture of initial material, catalyst andhydrogen in the liquid phase is passed from the preheater K into the reaction vesselL from which the products of the reaction are conducted to the cooler M and thence to separating vessel N which is provided with separate conduits for leading off gases and 'liquid products. w

The following examples will further illustrate the nature of this invention but the invention is not restricted to these examples. The parts are by weight.

r Example 1 Equal parts of very finely powdered yellow ammonium silico-molybdate, alumina hydrate (containing about 60 per cent of A1101 and kaolin are thoroughly mixed and then made into a paste with an equal w to! 30 per cent nitric acid. The mass is dried at C. and then slowly heated to about 470 C. until nitric acid vapors are no longer evolved.

The hard mass is brought into the form of pieces of suitable size by comminution and reduced by means of hydrogen in av high pressure vessel under a pressure of 200 atmospheres and {a temperature gradually rising to 450 C. Then, at 430 C., brown coal tar middle oil is added to the current of hydrogen insuch amounts that twice the volume of the catalyst of the said middle oil passes through the high-pressure vessel per hour.

When the reaction gases are cooled a waterclear condensate is obtained of which from to .70 per cent by volume bolls below 180 C. Of

these benzine hydrocarbons more than one third passes over below C.

If the yellow complex salt, before being mixed with alumina hydrate and kaolin, be heated to 450 (3., whereby ammonia and water of hydration escape, the procedure hereinbefore described may be followed with the same results.

Example 2 Equalparts of tungstic acid and chromic acid in dissolved state are mixed whereupon the resulting paste is evaporated to dryness and subsequently heated to 400 C. The resulting solid mass is comminuted. to grains and filled into a high pressure tube in which it is reduced in a stream of hydrogen under a pressure of 200 atmospheres and at a temperature gradually ris- 3 ing to 450 c. Then; at 420' c. the middle oii fraction of a German mineral oil is passed together with the stream of hydrogen through the said tube in an amount of 2.5 times the volume of the catalyst per hour. In this manner. the

same satisfactory yields of the desired products are obtained as in the foregoing example.

Example 3 I Ammonium hexamolybdo chromite prepared as described by Struve in the Journal fiir praktische Chemie, volume 61, pages 44'! and following, is brought into a solid form by pasting carbonaceous materials by catalytic destructive hydrogenation at atemperature between 300 and 700 C.'and under a pressure above 20 atmospheres, the step of working with a catalyst comprising a compound selected from the group consisting. :oi' the silico, molybdic acids and the silico tungstic acids and the salts of theseacids.

' PAUL HEROLD. 

